SpaceX Polaris Dawn crew set for historic private spacewalk

Washington: After trekking deeper into space than any humans in the last half century, a pioneering private crew is set to make history Thursday with...

Washington: After trekking deeper into space than any humans in the last half-century, a pioneering private crew is set to make history Thursday with the first-ever spacewalk by non-professional astronauts.

The SpaceX Polaris Dawn mission, led by fintech billionaire Jared Isaacman, launched early Tuesday from the Kennedy Space Center in Florida, reaching a peak altitude of 870 miles (1,400 kilometers).

That's more than three times higher than the International Space Station, in a region of space called the inner Van Allen radiation belt -- a zone teeming with dangerous, high-energy particles.

Now, with their Dragon spaceship's elliptical orbit reduced to a low point of roughly 120 miles and high of 430 miles, the crew of four is gearing up for the mission's centerpiece: an audacious extravehicular activity (EVA) scheduled for 0958 GMT on Thursday, with a backup window on Friday.

SpaceX pushed the time back by a few hours early Thursday, without explaining why. It plans a webcast of the event starting about an hour beforehand, on its website.